3, 3-dibutyl-2-(2, 2, 4-trimethylpentyl) pseudourea as an insect repellent



United States Patent poration of Delaware No drawing. Filed Aug. 17,1964, Ser. No. 390,228 7 Claims. (Cl. 167-22) This invention relates toinsect repellents, and particularly to novel repellent compositions anda novel method of repelling insects, particularly flies, roaches andrelated pests.

There has been substantial progress in the development of syntheticinsecticides which are effective to control and to kill undesiredinsects. However, particularly with respect to pests where ettectivecontrol by killing is diificrult, due to the nature of the pests or theenvironment, or where the health and comfort of man and animals may beconcerned, it may be usetul to repel such insects from environments inwhich their presence is undesirable. Thus, pests such as the cockroachand the housefly and stab-1e fly, which exist in close relationship toman and animals, are desirably repelled from association with man oranimals or with food or with waste products, to prevent the spread ofdisease. It is also desirable to use repellents to prevent the movementof such pests from one area to another. A long-lasting repellent isespecially desirable to avoid the need for continual re-application, orfor such uses as on shipping containers, for example, where continuingtreatment may not be feasible.

We have discovered that effective, long-lasting insect repellency may beachieved through use of repellent compositions comprising -an effectiveamount of the compound 3,3-dibutyl 2 (2,2,4-trimethylpentyl)pseudourea.These compositions may be used alone as repellents, or in conjunctionwith insecticidal compounds, to achieve longlasting and eflfectiveactivity. This active compound is characterized by a marked persistencyof repellent action, and has been found to be superior in performance tocommercially used repellents, in both initial and residual activity.

The chemical compound of this invention has the follow-ing structuralformula:

T he nomenclature of the above compound is subject to variation in thechemical literature, in that the terms pseudourea and isourea aresynonymous and are used interchangeably. For consistency, used herein isthe nomenclature recommended by Chemical Abstracts, i.e.,3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea.

The above compound may be prepared by the transalkylation reaction of2,2,4-trimethylpentyl alcohol with 2-methyl-3,31dibutylpseudourea, or byreaction of 2,2,4- trimethylpentyl alcohol with diblutylcyanamide in thepresence of a sodium alkoxide catalyst, as described by Fonman, Ericksonand Adelman, J. Org. Chem. 28, 2653 (1963). The intermediatedibutylcyanamide may be prepared according to the procedure outlined byW. L. Garbr-echt and R. M. Her-bst, J. Ong. Chem. 18 (1953). Preparativedetails are illustrated in the following example:

EXAMPLE I Six tenths gram of sodium was dissolved in 100 g. of2,2,4-trimethylpentyl alcohol and 125 ml. of benzene by refluxing themixture overnight, and 38.5 g. of 3,3-dibutyl- 2-methylpseudourea wasadded. The mixture was slowly distilled through a packed column toremove the methanol as the azeotrope with benzene. Sufiicient benzeneICC was added during the distillation to keep the pot temperature below110 C. When no more methanol could be obtained, the sodium alkylate inthe pot was neutralized with 2 ml. of glacial acetic acid, and themixture washed with 50 ml. of water. The benzene and excess alcohol weredistilled under vacuum, and the residue fract-ioned to yield 54 g. of3,3-dibutyl-2-(2,2,4-trimethylpentyl) pseudourea, boiling at 7074/0.002mm., n 1.4539, 1 0.8810.

Neutralization equivalent: Calcd, 284.5; found, 285.8.

Analysis.Calcd for C H N O: C, 71.78; H, 12.76; N, 9.85. Found: C,71.61; H, 12.70; N, 9.74.

This compound exhibits excellent repellency against the German cockroach(Blatella germonica), against houseflies (Musca domestica), stable flies(Stomoxys calcitmns (L.)) and other flying and crawling insects.

In carrying out this invention, repellent compositions comprising 3,3d-ibutyl 2 (2,2,4 trimethylphenyl) pseudourea may be applied in anysuitable fashion to the area in which insect repellenc-y is desired, inan amount and concentration effective to achieve such repellency.Repellent compositions may be applied, as is well known in the art, assolids or liquids, as sprays including pressurized space sprays, and inorganic or aqueous solution or dispersion.

Other usediul rformulations include emulsifiable concentrates foraqueous spray application, suitable for use on animals, in rooms,Warehouses, etc. Emulsifiable concentrates are homogeneous liquid orpaste compositions which are readily dispersed in water or otherdispersant, and may consist entirely of 3,3dibutyl-2-(2,2,4-trimethylpentyl)pseudourea with a liquid or solidemulsifying agent, or may also contain a liquid carrier, such as xylene,heavy aromatic naphthas, isophorone and other nonvolatile organicsolvents. For repellent application these concentrates are dispersed inwater or other liquid carrier, and normally applied as a spray to thearea to be treated. The percentage by weight of the essential activeingredient may vary according to the manner in which the composition isto be applied, but in general comprises 0.5 to percent of activeingredient by weight or the repellent composition.

Typical wetting, dispersing or emulsifying agents which may be used inrepellent formulations include, for example, the alkyl and alkylarylsulfonates and sulfates and their sodium salts; polyethylene oxides;sulfonated oils; fatty acid esters of polyhydric alcohols; and othertypes of surface active agents, many of which are available in commerce.The surface active agent, when used, normally comprises from 1 percentto 15 percent by weight of the repellent composition.

The repellent may be applied as a dry dust, particularly for control ofnon-flying insects such as roaches. The active repellent is admixed withfinely divided solids such as talc, attapulgite clay, kieselguhr, andother organicand inorganic solids which act as dispersants and carriersfor the toxicant; these finely divided solids have an average particlesize of less than about 50 microns. Since the instant toxicant is anoily liquid, an absorbent dust can accommodate high concentrations ofactive ingredient, if desired. A typical dust formulation, usefulherein, is one containing 10.0 parts of3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea, 30.0 parts of bentoniteclay and 60.0 parts talc.

Wettable powders, also useful formulations for repellents, are in theform of finely divided particles which disperse readily in water orother dispersant. The wet table powder may be ultimately applied to thearea either as a dry dust or as an emulsion in water or other liquid.Typical carriers for wettable powders include Fullers earth, kaolinclays, silicas, and other highly absorbent, readily wet inorganicdiluents. Wettable powders normally are prepared to contain about 80%active ingredient, depending on the absorbency of the carrier, andusually also contain a small amount of a wetting, dispersing oremulsifying agent to facilitate dispersion. For example, a usefulwettable powder formulation contains 25.0 parts of3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea, 72.0 parts of bentoniteclay and 1.5 parts each of sodium lignosulfonate and sodiumlaurylsulfonate as wetting agents.

Other useful formulations for repellent applications include simplesolutions of the active ingredient in a dispersant in which it iscompletely soluble at the desired concentration, such as acetone,alcohols, naphthas, kerosene, aromatic and aliphatic liquid hydrocarbonsincluding benzene, xylene, cresol, and the like. The choice of solventmay depend on the desired mode and situs of application.

Granular formulations, wherein the toxicant is carried on relativelycoarse particles, are of particular utility for distribution to repelcrawling insects. Pressurized sprays, typically aerosols wherein theactive ingredient is dispersed in finely divided form as a result ofvaporization of a low boiling dispersant solvent carrier, such as theFreons, may also be used.

In addition, the active repellent may be combined with otherconventional materials and toxicants to impart repellency to pesticidalformulations. In application in areas containing growing plants,attention should be given to the phytotoxicity of the compound of thisinvention.

The oncentration of 3,3-dibutyla2a(2,2,4-trimethylpentyl)pseudourea inthese formulations may vary from 0.001 to about 95 percent by weight,depending on the formulation. In liquid solution or dispersion, aqueousor organic, preferred concentrations are generally in the range of 0.01to 5 percent by weight. Liquid and solid concentrates may contain fromabout 2.5 to 95 percent by weight of active repellent. Solid dusts andgranular formulations may contain as little as 0.001 to over 50 percentby weight of repellent. A very broad latitude and choice of type andconcentration of formulation is available. It is important merely thatenough of the repellent composition be applied, in the situs in whichrepellency is desired, to deposit a repellent amount and concentrationof the active ingredient. As is well known in this art, the degree ofeffectiveness of a toxicant may vary with the formulation and method ofapplication.

The repellent activity of3,3-dibutyl-2-(2,2,4-trirnethylpentyl)pseudourea is exemplified furtheras follows:

EXAMPLE II Repellen-cy against the German cockroach was evaluated by thegeneral method of Goodhue, J. Econ. Entom. 53, 805 (1960). File cards,3" x 5", were dipped in an acetone solution of the test compound, andallowed to dry. The cards were placed in a slanting position against thesides of a clear plastic box containing about two thousand Germancockroaches. The number of roaches resting on the treated cards werecounted at specified intervals, and compared with an untreated controlto determine the repellency, calculated according to the followingformula:

Percent repellenc (No. on control card-No. on treated card) X 100 No. oncontrol card The cards were left in each box for six hours each day, andthe repellency was determined at intervals during each six hour period.The same cards were replaced on successive days, to ascertain the effectof deposit age on repellency. Results are shown in the following table,wherein Deposit Age refers to the period which elapsed between the timeof treatment of the cards and the initiation of that days exposure ofthe roaches to the cards. The Exposure Time is the period of time, eachday, dur- &

ing which the roaches were exposed to the treated cards. The compound ofthis invention is compared with the commercial cockroach repellent R-ll(l,5a,6,9,9a,9bhexahydro-4a 4H -dibenzofurancarboxaldchyde) 5 Table1.-Rcpellency against the German cockroach Concn. Percent Repelleney inAce- Deposit Exposure Time (Hours) Material tone, Age

10 percent (Days) 0 100 100 100 5. 0 1 100 100 100 100 2 100 100 100 3.3-dibutyl-2-(2, 2, 4- 0 100 100 100 trimethylpentyl) 2. 5 1 100 100 100100 pseudourea 2 100 100 100 0 100 100 100 1. 25 l 100 100 100 100 2 100100 100 100 0 100 100 100 5. 0 1 98. 5 98. 6 99. 1 98. 1 It-11" 2 0 7.19.2 0 98. 0 100 9,9. 5 W 2. 5 1 80. 5 78. 7 40. 5 35. 7 2 0 0. 8

It is seen that the compound of this invention is a very efficient andlong-lived roach repellent, and compares very favorably with a standardrepellent.

EXAMPLE III Table 2.Repellency against the German cockroach PercentRepellency Deposit Age (Days) 3, 3-dibutyl-2-(2, 2, 4- R-lltrimethylpentyl) pseudourea EXAMPLE IV This compound was evaluated as ahousefly repellent, following the Bruce turntable method, as follows:Filter papers, 5.5 cm. in diameter, were treated with 0.05 ml. of anacetone solution of the test material at the concentrations specified inthe table, and dried. The filter papers Were formed into cones and theinverted cones placed in small hollow plastic stoppers on the peripheryof a slowlyrevolving screen turntable within a large plastic box. Smallweighed lactose pellets were placed within the cones so that the feedingflies would be forced to rest on the treated paper. Untreated filterpaper cones containing weighed lactose pellets were included ascontrols. The turntable was exposed for a period of one hour tohousefiies (Musca domestica) which previously had been starved for onehour. After this period the pellets were reweighed and the loss inweight of pellets in the treated samples was compared with that of theuntreated controls, to give a quantitative measure of the degree ofrepellency. Results are shown in Table 3 below.

Table 3 .Repellency against houseflies Concentration, percent: Percentrepellency It is seen that the compound of this invention exhibitsexcellent repellency against housefiies.

EXAMPLE V Table 4.Repellency against stable flies Concentra- Average,Compound tion in Percent Acetone, Repellency Percent3,3-dibutyl-2-(2,2,4-trimethylpentyl) 2. 5 100 pseudourea 1. 25 100 0.6291 Crag Fly Repellent 2. 5 55 The above data show the compound of theinstant invention to be an excellent repellent against stable flies,under conditions designed to simulate field experience.

It is apparent that variations and modifications may be made within thescope of the foregoing disclosure and the appended claims, withoutdeparting from the essential principles of this invention.

We claim:

1. An insect repellent composition comprising as an essential ingredientan effective amount of 3,3-dibutyl-2- (2,2,4-trimethylpentyl)pseudoureaand a carrier.

2. An insect repellent composition comprising3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea and an inert adjuvant inadmixture therewith, wherein said pseudourea is present in an amount offrom 0.001 to about percent by weight.

3. An insect repellent composition comprising3,3-dibutyl-Z-(2,2,4-trimethylpentyl)pseudourea and a dispersing agentin admixture therewith, wherein said pseudourea is present in an amountof from 0.001 to about 95 percent by weight.

4. A method of repelling insects which comprises subjecting such insectsto the action of an effective quantity of3,3-dibuty1-2-(2,2,4-trimethylpentyl)pseudourea.

5. 3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea.

6. A roach repellent composition comprising3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea and an inert adjuvant inadmixture therewith, wherein said pseudourea is present in an amount offrom 0.001 to about 95 percent by weight.

7. A method of repelling roaches which comprises subjecting roaches tothe action of an effective quantity of3,3-dibutyl-2-(2,2,4-trimethylpentyl)pseudourea.

No references cited.

JULIAN S. LEVITT, Primary Examiner.

V. C. CLARKE, Assistant Examiner.

4. A METHOD OF REPELLING INSECTS WHICH COMPRISES SUBJECTING SUCH INSECTSTO THE ACTION OF AN EFFECTIVE QUANTITY OF3,3-DIBUTYL-2-(2,2,4-TRIMETHYLPENTYL)PSEUDOUREA.